The present invention relates to an openable roof capable of opening and closing a central portion thereof. The openable roof is typically used in a temporary structure for an event site or the like, though the applicational field is not limited to them.
Applicants of this invention have already filed a patent application relating to a roof capable of being opened and closed. The prior patent application is related to an openable roof for creating a so-called closed space when the top is closed by a movable roof section and creating an open space when the top is open.
FIGS. 13 through 15 of the attached drawings show an example of the openable roof which is disclosed in Japanese Patent Application No. Sho 61-81858 entitled "Movable Roof".
As shown in FIGS. 13 and 14, the movable roof or the openable roof 1 comprises a movable roof section which is composed of a plurality of roof units 2 formed into a sectorial shape. The roof units 2 are angularly movable about a center of rotation of the sectorial shape, whereby the movable roof section can open and close the roof building subject or a site L. The roof units 2 jointly use the common center of rotation. As shown in FIG. 15, a first support leg 3 and a second support leg 4 supporting each roof unit 2 are arranged respectively adjacent an arc of the sectorial shape forming the roof unit 2 and adjacent the center of rotation. The first and second legs 3 and 4 are provided respectively with slide mechanisms which are movable respectively along arcuate tracks 5 and 6.
An upper space above seats 8 is closed by a stationary roof section 7. In addition, although illustration is omitted, the first support leg 3 has its lower end which is provided with a drive device. By the drive device, wheels engaged with the track 5 travel along the same.
According to the openable roof 1, it is possible to angularly move the roof units 2 about the center of rotation that is the center of the sectorial shape. For instance, as illustrated in FIG. 14, in case where the openable roof 1 comprises four roof units 2, these four roof units 2 can be arranged in adjacent relation to each other to uniformly close or cover the upper portion of the roof building subject L. On the other hand, the adjacent four roof units 2 can be spaced two by two away from each other toward the stationary roof section 7, thereby opening the upper portion of the roof building subject L.
By the way, the openable roof 1 has such superior advantages that the movable roof section can be built and withdrawn with respect to the roof building subject L optionally and easily, whereby it is possible to freely cope with the weather and so on. However, the openable roof 1 has the following drawback.
That is, particularly, in the circular or sectorial roof, in case where the movable roof section is divided into a plurality of sectorial roof units which are angularly movable about the center of rotation to open and close the roof building subject L, a post 9 is required to be provided at the center of rotation, that is, at the center of the roof building subject L. The post 9 is an obstacle to effective utilization of the vast roof building subject L.